The question of how military service shapes men's life course trajectories has received limited but sustained attention in the literature for more than 25 years. Although there have been many studies that have examined psychological health, research on the impact of military service on physical health outcomes in later-life has been limited. There is a substantial literature on the physical health of veterans;however this literature focuses on veterans only or on comparisons of veterans from different wars, and often does not examine differences in health trajectories between veterans and nonveterans. Therefore, this project will use nationally representative longitudinal data from the Health and Retirement Survey (MRS) to investigate the trajectories of health conditions, self-rated health, functional limitations, and disability among men who did and did not serve in the military. The specific project aims are to: 1) Describe how health trajectories vary in relation to military service. 2) Specify whether enlistment age, wartime service, length of service, and military-related disability have different effects on later life health trajectories. 3) Examine whether military service mediates or moderates the effects of early-life disadvantage on health trajectories. 4) Consider whether mid- to late-life characteristics mediate the effects of early-life disadvantages or military service on later-life health trajectories. 5) Determine the extent to which these effects vary across cohorts who served during different historical time periods. Growth curve models will be estimated separately for four cohorts that include veterans of WWI, WWII, Korea, and Vietnam. In addition, we consider the effects of selection into military service, unobserved pre- HRS mortality selection, and mortality selection that occurred during the MRS data collection period. Overall, this project will contribute to the science of aging by providing insight into whether early-life participation in a particular social institution (i.e., the military) in specific historical periods shapes the process of cumulative (dis)advantage that leads to later-life health disparities.